Stoker



L. R. STOWE Dec. 25, 1934.

STOKER s Sheets-Sheet 1 1 Filed Nov. 12, 1931 INVENTOR. Z 0 4 Z $50406 BY 3* ATTORNEYS.

5 Sheets-Sheer, 2

STOKER L. R. STOWE Fild NOV. 12, 1951 Dec. 25, 1934.

y INVENTOR. Loyal zfi z awe BY 9 ATTORNEYS Dec. 25, 1934. R. STQWE 1,985,625

STOKER Filed Nov. 12, 1931 3 Sheets-Sheet 5 IZ i I N VEN TOR.

L 02 5? 76 Sim/e BY A TTORNEYS.

Patented Dec. 25, 1934 UNITED STATES PATENT oFFIca Claims.

The present invention relating as indicated to van improvement in stokers, or mechanically operated furnaces, has more precise reference to a device controlling the rate or mode of ash discharge .5 in a chain or endless type of stoker.

Heretofore means for crushing and grinding the ashes, clinkers, and refuse from a mechanically operated furnace have been used in conjunction with that type of stoker conventionally known as an under-feed stoker. It has been found, however, that a clinker grinder couldnot be efficiently and operatively employed with a chain grate due to the fact that the juxtaposition of a plurality of moving parts at the rear or ash discharge endof the endless grate resulted in a .breakingup of the fuel bed, with the resultant short circuiting of the air currents as well as ex posing the moving parts to the corroding and deteriorating action of the heat of the furnace.

The fundamental object of the present invention is to provide an external housing and dividing wall to extend over and enclose the rear end of the endless grate surface and to serve as a surface for uniformly conveying the fuel bed from the grate to the clinker grinder, as well'as to isolate the moving parts of the chain grate mechanism from the moving parts or" the clinker grinder mechanism. It is a further object to provide coincident novel structural expedients which tend to perfect the operability and efficiency of the grate construction embodying the principle of my invention. Some of the above mentioned c0- incident structural features may be here briefly summarized as consisting of an individual chain take-up, cover plate, anchor bolts, sea-ling flanges for the clinker grinder and inclination of the grate surface. The objects, advantages, and corelation of the above mentioned features shall become manifest during the course of the following description. To the accomplishment of the foregoing and related ends, said invention, then, consists of the means hereinafter fully described and particularly pointed out in the claims.

The annexed drawings and the following description set forth in detail certain mechanism embodying the invention, such disclosed means constituting, however, but one of various mechanical forms in which the principle of the invention may be used.

In said annexed drawings:

Fig. 1 is an elevational view more or less diagrammatic of the conventional type of boilersetting showing the manner of installation of the chain grate stoker and improvements provided ace cording to the principle of my invention; Fig. 2 is an enlarged, detailed elevational view of the ash discharge end of the chain grate; Fig. 3 is a detail sectional view of the chain take-up mechanism, being a section taken substantially .along the line 3-3 of Fig. 2; Fig. 4 is a section taken substantially along line 4 of Figl-B;

Referring more particularly to Fig. l, I have shown a furnace and boiler setting having the fire arch indicated generally at l, the bridge wall 2,

and the chain grate stoker 3 installed in the furnace. A fuel feeding tube 4 leads into the hopper 5 which is disposed at the front end of the chain grate 3. At the rear or ash discharge end of the chain grate 3, there is positioned the cover plate and dividing wall assembly indicated generally by the numeral 6 which serves to uniformly direct the ashes and refuse on to the clinker grinder drums7, and to act as an air seal at the rear end of the grate. The ash pit 8 is placed immediately below the clinker grinder 7. A large access chamber 9 is positioned at the lowermost part of the furnace assembly and is suitably connected to the ash pit 8 by means of a closable opening 10. Additional openings 11 and '12 in the refuse chamber 9 serve as means for collecting siftings, ashes and refuse from points immediately below the chain grate. Air is fed to the furnace through the inlet manifold 13. A series of dampers 14 positioned along the under side of the chain grate surface serve as means for regulating the inlet air currents and correspondingly for aiding in the controlling of the rate of fuel-combustion. A bafile plate 15 encloses the front end of the chain grate in order to prevent 1 short circuiting of the inlet air through the feed hopper and driving mechanism.

Directing attention to Fig. 2, the ends of the chain grates 3 are carried upon a plurality of sprocket wheels 20, (only one of which is shown), said wheels being rotatably mountedin the supporting arms 21 by means of the idler shaft 22 carried in the longitudinal channels 23. The

supporting arms 21 are bolted at their lower ends to the transverse frame beam 24. q

The cover plate 25 is adapted tosubstantially contact with the chain grate surface at the point 26. The cover plate 25 extends completely across the width of the grate and may be constructed in a plurality of longitudinal sections in order to facilitate manufacture as Well as to substantially defray the cost of repair and replacements, and tominimize the effect of checking andwarping. Immediately contiguous .to the endof the cover plate 25, there is placed the apron 2'7 which functions as a means for guiding the ashes and refuse on to the clinker grinder drums '7. A dividing wall 28 which is assembled in conjunction with the cover plate 25 extends entirely across the discharge end of the grate assembly and serves as a means for confining the air blast, so that there shall be no short circuiting of the blast through the ash discharge. An arcuately formed flange or projection 29 similar to the apron 2'7 is positioned upon the rear wall 2 by means of the transverse channel beam 30. The projection 29 serves not only as a partial seal between the wall 2 and the clinker grinder '7, but also as a means for dislodging large particles which might become caught between the teeth of the grinder.

It will be noted that there is a substantial change in the degree of inclination of the chain grate surface at the point 31. Such a change in angular inclination is for the purpose of utilizing the influence of gravity in order to aid in the feed of the fuel bed over the cover plate edge 26.

It is also of paramount importance for the operable efliciency of my controlled ash discharge that there be provided means for retaining the chain grate 3 in close proximity to the cover plate edge at 26. I contemplate the accomplishment of the foregoing objective by means of providing the individual take-ups for the endless grates. It is well known in the art that there occurs a certain amount of growth in cast iron upon alternating heating and cooling, the result being that in an endless chain grate there will occur an increase in the length of the chain with the corresponding tendency to sag and hang loose.

Referring to Figs. 3 and 4 the means which I have provided for the individual chain take-ups consist of the U-shaped yoke 32 having positioned in its outer ends, the sprocket wheel idler shaft 22. The ends of the idler shaft 22 are in the form of flats and are adapted to slide in the channels 23 of the supporting arms 21. The other end of the U-shaped yoke 32 has a hole drilled therein for the reception of the threaded bolt 33 which is secured at its one end to the transverse guide block 34 and threadably engages at its other end with the adjusting nut 35. It will thus be seen that by advancing the adjusting nut upon the threads of the bolt 33, that the yoke 32 will be correspondingly forced towards the end frame 24 of the chain grate.

In order to firmly secure the upper edges 26 of the cover plates 25, and to prevent their misalignment and warping, there is provided the stationary grate bar 40 having a longitudinally projecting lug 41 which in turn engages with the corresponding groove in the center web 42 of the cover plate. The stationary grate bar 40 has on its under side a downwardly projecting boss 43 in which is connected the hook bolt 44. The other end of the hook bolt 44 fastens to the plate 45 which is in turn secured to the under side of the transverse bar 46 by means of the bolts 47 and 48. A transverse frame beam 50 supports the stationary grate bar 40 and the web 42 of the cover plate 25. The transverse bar 46 may be secured at each end to the side frames (not shown) of the stoker, and serves the further function of supporting the chain take-up assembly.

It will thus be seen that I have provided a relatively simple and efficient means for effecting the utilization of a clinker grinder in conjunction with a chain grate stoker, in addition to the advantageous features alreadyenumerated, re-

sulting in a mechanism of economical operation and durability.

Other modes of applying the principle of my invention may be employed instead of the one explained, change being made as regards the mechanism herein disclosed, provided the means stated by any of the following claims or the equivalent of such stated means be employed.

I therefore particularly point out and distinctly claim as my invention:

1. In a chain grate stoker, the combination of a frame member, a plurality of endless chains, a clinker grinding means disposed adjacent the ash discharge end of said stoker, a cover plate positioned over said discharge end, downwardly extending lugs on the end of said cover plate closest to the feed end of the stoker, and fastening means engaging said lugs and securing the latter to the frame of the stoker.

2. In a chain grate stoker, the combination of a plurality of endless chains, a clinker grinding means disposed adjacent the ash discharge end of said stoker, a rear furnace wall adjacent said clinker grinding means, a cover plate extending over the grate surface of the ash discharge end of said stoker, a dividing wall between said clinker grinding means and said discharge end, projecting portions on said dividing wall and said rear wall extending toward the outer periphery of said clinker grinding means, and adjustable means for regulating the tension of said chains, said adjustable means being individual to each chain.

3. In a chain grate stoker, the combination of a clinker grinding means disposed adjacent the ash discharge end of said stoker, a cover plate p0- sitioned over said discharge end and extending to a point adjacent said clinker grinder, and means for securing the upper transverse edge of said cover plate closest to the feed end of said stoke-r to the frame of said stoker.

4. In a chain grate stoker, the combination of a plurality of endless chains, a clinker grinding means disposed adjacent the ash discharge end of said stoker, a rear furnace wall adjacent said clinker grinding means, a cover plate extending over the grate surface of the ash discharge end of said stoker, a dividing wall between said clinker grinding means and said discharge end, projecting portions on said dividing wall and said rear wall extending toward the outer periphery of said clinker grinding means, adjustable means for regulating the tension of said chains, said adjustable means being individual to each chain, and means for securing the edge of said cover plate closest to the feed end of said stoker to the frame of said stoker,

5. In a chain grate stoker, the combination of a plurality of endless chains, said chains having an increase in angular inclination in their ash discharge end portion, a clinker grinding means disposed adjacent the ash discharge end of said stoker, a rear furnace wall adjacent said clinker grinding means, a cover plate extending over the grate surface of the ash discharge end of said stoker, a dividing wall between said clinker grinding means and said discharge end, projecting portions on said dividing wall and said rear wall extending toward the outer periphery of said clinker grinding means, and adjustable' 

